Capacity constraint scenarios are essential for assessing potential grid limitations when evaluating Points of Interconnection (POIs) for available capacity. This glossary includes all the standard terms used with these scenarios.
Scenario
N-1: Contingencies are applied.
N-0: No contingencies are applied.
Read more here about the different scenarios and when to use each.
Upgrade order
Order in which constraints occur based on increasing injection/withdrawal amounts.
Injection/withdrawal before upgrade
Injection: This analysis determines the maximum power you can inject into a Point of Interconnection (POI). It is valuable for assessing the impacts of new generation sources such as solar plants, wind, or energy storage projects injecting power into the grid.
What is the maximum MW that can be injected into the grid before an upgrade of the limiting element in this data row becomes necessary?
Withdrawal: This analysis determines the maximum power you can draw from a Point of Interconnection (POI). It is valuable for assessing the impacts of new power consumption, such as data centers (that require sufficient energy to power) or energy storage projects that charge from the electricity grid.
What is the maximum MW capacity of energy withdrawal from the grid permitted by the limiting element in this row before an upgrade is required?
Injection/withdrawal after upgrade
For Injection layers (which determine the injection capacity of a new solar or wind plant), this value indicates the potential increase in injected MW, if any, following an upgrade of the limiting element specified in this data row.
For Withdrawal layers (where the battery system may be charged from the grid), this indicates the maximum MW that can be withdrawn, if any, once the limiting element specified in this row is upgraded.
Limiting element description
This is the full description of the limiting element that needs to be upgraded to increase the injection/withdrawal amount. This description includes the names (if known) of each connecting bus (which will be the same for a transformer) and each voltage (which will be the same for a transmission line). If the names are not known, the ID can be used to help identify the element.
Distribution factor (DFax)
The Distribution factor (Dfax), expressed as a percentage, signifies the linear sensitivities of the generators at the source and sink. Calculated based on subsystem considerations, this value is a crucial criterion, as outlined in the utility study methodology, for determining the eligible monitored facility that will require network upgrades. Ultimately, the Dfax is an important indicator of the need for an upgrade.
Binding contingency identifier
In the N-1 Scenario, this will display the associated contingency (see View study assumptions for more information). Some markets include codes that help determine the type of contingency.
Limiting element base rating
The rating of the limiting element under normal or operating conditions.
Limiting element contingency rating
The rating of the limiting element under contingency or emergency conditions.
Substation bus number or branch number
This is the bus/line number selected from the headroom bus layer. This is the point-of-interconnection evaluated for potential grid constraints. This number repeats in this table.
Substation description or branch description
Substation name including voltage and ID. The ID may include the specific breaker and is a unique identifier. This description repeats in this table.
Injection/withdrawal after upgrading pre-existing limiting elements MW
Injecting/Withdrawing more than this headroom capacity will cause network upgrades beyond those that are pre-existing. This number repeats in this table.
Pre-existing limiting element
This indicates whether or not this row’s specific limiting element was a pre-existing issue. “The pre-existing issues are the network impacts identified due to the prior queue dispatch and the power injection modeled is contributing to it.” See View study assumptions for more information.
Count of pre-existing limiting elements
The count of pre-existing issues for a given point-of-interconnection. This number repeats in the table.